State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China.
State Key Joint Laboratory on Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China; Institute for Environmental Genomics, Department of Microbiology and Plant Biology, The University of Oklahoma, Norman, OK, USA.
Sci Total Environ. 2020 Jul 10;725:138504. doi: 10.1016/j.scitotenv.2020.138504. Epub 2020 Apr 6.
Nitrous oxide (NO) is an important greenhouse gas contributing to global climate change. Emissions of NO from acidic forests are increasing rapidly; however, little is known about the mechanisms driving these emissions. We analyzed soil samples from a high NO emission area (HEA, 224-601 μg N m h) and an adjacent low emission area (LEA, 20-30 μg N m h) of a highly acidified forest. HEA showed similar carbon and nitrogen (N) pools and microbial biomass to LEA, but significantly higher moisture and extractable nutrients than LEA did. GeoChip 4 detected 298 gene families (unadjusted P < 0.05; 94, adjusted P < 0.05) showing significantly different structures between HEA and LEA. Both areas had highly diverse N cycling functional genes. However, HEA had higher relative abundances of nor, P450nor, and archaeal nitrifier nirK, which provided evidence for the importance of denitrifiers in NO emission. HEA also showed significantly higher relative abundances of lignin- and cellulose-degrading genes, oxygen-limitation-response genes and denitrifier ppk, but lower abundances of N- and phosphorus (P) -limitation-response genes especially denitrifier pstS, corresponding to the higher moisture and extractable nutrients conducive to denitrification. The moisture, extractable nutrients and pH explained over 50% variation in microbial communities, and extractable P appeared as the key factor driving community variation and consequently regulated NO production. CAPSULE ABSTRACT: NO emission in highly acidified forest soils was related to the diverse N functional genes, especially denitrification genes, and was affected by soil properties.
一氧化二氮（NO）是一种重要的温室气体，导致全球气候变化。酸性森林中 NO 的排放迅速增加；然而，对于驱动这些排放的机制知之甚少。我们分析了高 NO 排放区（HEA，224-601μgN m h）和相邻低排放区（LEA，20-30μgN m h）的土壤样本来自高度酸化的森林。HEA 显示出与 LEA 相似的碳和氮（N）库和微生物生物量，但水分和可提取养分明显高于 LEA。GeoChip 4 检测到 298 个基因家族（未调整 P < 0.05；94 个，调整 P < 0.05），显示 HEA 和 LEA 之间的结构有明显差异。两个区域都有高度多样化的 N 循环功能基因。然而，HEA 中 nor、P450nor 和古生菌硝化作用 nirK 的相对丰度较高，这为反硝化作用在 NO 排放中的重要性提供了证据。HEA 还显示出明显较高的木质素和纤维素降解基因、氧气限制反应基因和反硝化作用 ppk 的相对丰度，但 N 和磷（P）限制反应基因的丰度较低，特别是反硝化作用 pstS，这与较高的水分和可提取养分有利于反硝化作用相对应。水分、可提取养分和 pH 解释了微生物群落超过 50%的变化，可提取 P 似乎是驱动群落变化的关键因素，从而调节 NO 的产生。摘要胶囊：高度酸化森林土壤中的 NO 排放与多样化的 N 功能基因有关，特别是反硝化基因，并受土壤性质的影响。
